Novel esters of polyfluoroisoalkoxy alkanols

ABSTRACT

COMPOUNDS OF THE FORMULA:   R1-CF(-R2)-CF(-CF(-R3)(-R4))-O-(CF2)X-(CH2)Y-OOC-(R5)N-CH3   WHEREIN (A) R1-R4 ARE EACH INDEPENDENTLY SELECTWED FROM THE GROUP CONSISTING OF F, CL AND PERFLUOROALKYL, AND TOGETHER CAN FORM A PERFLUOROCYCLOALKYLENE GROUP, WITH THE PROVISO THAT R1-R4 MAY NOT CONTAIN MORE THAN TWO CHLORINE ATOMS, (B) X IS AN INTEGER FROM 1-81, (C) Y IS AN INTEGER FROM 1-81, (D) R5 IS A DIVALENT ALKYLENE GROUP HAVING FROM 1-22 CARBON ATOMS, AND (E) Z IS 0 OR 1, ARE USEFUL AS INSULATOR AND CONDENSER FLUIDS, HYDRAULIC FLUIDS, LUBRICANTS AND HEAT TRANSFER MEDIA. THESE COMPOUNDS ARE ALSO SURFACE ACTIVE AND ARE USEFUL AS ANTI-WETTING AGENTS.

United States Patent Office 3,754,009 Patented Aug. 21, 1973 3,754,009 NOVEL ESTERS OF POLYFLUOROISOALKOXY ALKANOLS Louis G. Anello, Orchard Park, Richard F. Sweeney, Elma, N.Y., and Morton H. Litt, Cuyalloga, Ohio, assignors to Allied Chemical Corporation, New York,

No Drawing. Continuation-impart of application Ser. No. 633,359, Apr. 25, 1967. This application May 25, 1970, Ser. No. 40,341

Int. Cl. Cllc 3/00; C07c 69/02 US. Cl. 260-408 20 Claims ABSTRACT OF THE DISCLOSURE Compounds of the formula:

R1 F-d-R, F-1-O(CF )X(CH ),OL-(Rsh-CHs CROSS-REFERENCES TO RELATED APPLICATIONS (1) This application is a continuation-in-part of copending application of Anello et al., entitled Telomers and Process for the Preparation Thereof, Ser. No. 633,- 359, filed Apr. 25, 1967, now US. Pat. No. 3,514,487.

(2) US. Pat. 3,453,333 to Litt et al., entitled Fluorinated Ethers, issued July 1, 1969.

(3) Copending application of Litt et al., entitled Fluorinated Ethers, Ser. No. 513,574, filed Dec. 13, 1965, now US. Pat. No. 3,470,256.

(4) Copending application of Anello et al., entitled Novel Fluorinated Alcohols, Ser. No. 721,089, filed Apr. 12, 1968, now abandoned.

These applications and patent are hereby incorporated by reference.

SUMMARY OF THE INVENTION This invention relates to novel esters of polyfiuoroisoalkoxy alkanols having the general formula:

wherein (a) R -R, are each independently selected from the group consisting of F, Cl and perfluoroalkyl, and together can form a perfluorocycloalkylene group, with the proviso that R R may not contain more than two chlorine atoms, (b) x is an integer from 1-81, (c) y is an integer from 1-81, (d) R is a divalent alkylene group having from 1-22 carbon atoms, and (e) z is 0 or 1.

The criticality in the structure of these compounds is in the polyfluoroisoalkoxyalkyl tail portion of the molecule wherein a carbon atom links an oxygen atom and a fluorine atom and wherein two fluoroalkyl linkages satisfy the remaining valences of the carbon atom linking the oxygen and fluorine atoms. The fluoroalkyl linkages are characterized by the presence of at least one fluorine atom on each carbon atom which is adjacent the carbon atom which links the oxygen and fluorine atoms. The fiuoroalkyl linkages may, when taken together, form a perfluorocycloalkylene structure. The term polyfluoroisoalkoxyalkyl herein shall be understood as including such cycloaliphatic structures.

In the above Formula I, R R may be the same or different. When the R R groups are perfluoroalkyl, the perfluoroalkyl group may be straight-chain or branchedchain.

Similarly, the R group, which is a divalent alkylene group, may be straight-chain or branched-chain.

The alkanol esters of the invention are thermally stable and are useful as heat transfer agents, hydraulic fluids, gyro-fluids, lubricants, and as insulator and condenser fluids. Specific useful applications include use as vapor phase coolants and dielectrics for electrical equipment and as temperature differential fluids in thermometric devices.

The alkanol-esters of the invention exhibit excellent surface activity and may be used as anti-Wetting agents by conventional techniques. The anti-wetting properties may be taken advantage, for example, in improving heat transfer in heat exchangers by coating the heat exchange surfaces with the liquid alkanol-esters, or solvent solutions of the same. Thus, a better heat transfer is effected between surfaces in which the condensate does not wet the heat exchanger surfaces, as compared with surfaces in which the condensate does Wet the heat exchange surfaces. As is further well-known in the art, anti-wetting agents are useful as coatings on the interiors of containers. The non-wettable surfaces thus produced make it possible to dispense liquid materials from the containers without leaving a residue. Yet another example of the use of non-wetting agents is in the treatment of paper and textiles to impart water and oil repellency thereto. The alkanol esters may be applied from any convenient solvent medium. Illustrative useful solvents from which the novel alkanol-esters may be applied to substrates to be treated include 1,1,2-trichlorotrifluoroethane, trichloroethylene and toluene. The solutions of the alkanol-esters are applied to the substrates by conventional dipping, spraying or brushing techniques and the treated substrates are then dried to remove the solvent.

DETAILED DESCRIPTION OF THE INVENTION AND OF THE PREFERRED EMBODIMENTS Referring to Formula I above, the R -R groups are preferably all P. When R R are perfluoroalkyl groups, the preferred carbon content is from 1-6. When Il -R form a perfluorocycloalkylene group, the preferred carbon content of the cyclic ring is from 4-6.

The divalent alkylene group may be straight-chain or branched-chain but, in the preferred embodiment, is straight-chain. The preferred carbon content for the R group is from 1-10.

Preferably, x and y are each 1-20, still 1-15, the preferred embodiment, z is 1.

In the preferred embodiment, z is 1.

The compounds of the invention may be prepared as described in parent application Ser. No. 633,359, mentioned supra, by reacting a corresponding telomer of the formula:

preferably from wherein X is H or F and R and z are as defined above, followed by reducing the resulting iodo containin compound with LiAlH, or with zinc and alcohol to substitute a hydrogen atom for the iodine atom.

Preparation of the telomer precursors of Formula II will be discussed in more detail hereinafter.

The unsaturated esters of Formula III are a known class of compounds.

The compounds of the invention are preferably prepared from the corresponding polyfiuoroisoalkoxy alkanols of the formula:

R: (IV) wherein R R x and y are as defined above, by reacting such alcohols with a saturated aliphatic carboxylic acid of the following formula:

CH3(R5); -OH (V) wherein R and z are as defined above, or with an acid halide of such acids.

The esterification reaction is conventional. The reaction may be carried out in the presence of an inert solvent medium, such as benzene, toluene, or carbon tetrachloride. If the free acid is employed as reactant, a small quantity of a mineral acid, such as sulfuric acid, may be added to serve as catalyst. If an acid halide is employed as reactant, the reaction may be expedited by the presence of a hydrogen halide acceptor, such as pyridine, in stoichiometric proportions with the acid halide reactant. The preferred acid halide reactant is the acid chloride. The esterification reaction proceeds satisfactorily from about 60 C. to the reflux temperature of the reaction mixture. The preferred operating temperature is the reflux temperature of the reaction mixture. The esterified product may be purified by fractional distillation.

The saturated aliphatic carboxylic acid starting materials belong to a well-known class of compounds.

The alcohol starting materials are prepared by a variety of routes depending on Whether x and y in above Formula IV are odd or even and upon the lengths of the various chains. Alcohols wherein x and y are both even integers may be prepared by reacting a telomer of the formula:

wherein x and y are even integers, with S0, to produce the corresponding polysulfate, followed by hydrolysis of the polysulfate with 35-50% H 50 at about 100 C. to the desired alcohol.

When x in Formula 1V is to be an odd number from 1 to 19 inclusive and y is to be 1, the alcohols can be prepared by reacting the perhaloisoalkoxy alkyl iodide wherein x is an even number from 2 to 20, and y is zero, 1.e.

with S0, to form a mixture of the acyl fluoride and the perhaloalkoxy fluoroalkyl pyrosulfuryl fluoride, reacting the combined reaction products with an alcohol such as methanol, ethanol, and the like, to produce the ester and reducing the ester to the alcohol with lithium aluminum hydride (LiAlH as a reducing agent.

When at is an even number from 2-20 and y is 1, the alcohol may be prepared by treating the telomer iodide of a compound having the desired final number of -CF groups and two -CH groups with alcoholic KOI-I to remove the iodine and form the perhaloisopropoxy fluoroalkyl ethene, oxidizing the ethene with KMnO to the acid, converting the acid to a lower alkyl ester and reducing the ester to the alcohol with lithium aluminum hydride.

When x is an even number from 2 to 20, and y is an odd or even number from 3 to 20, the alcohol may be produced by reduction of the corresponding iodo alcohol With lithium aluminum hydride (LiAlH or with Zinc and alcohol. The iodo alcohol starting materials may be prepared by reacting a perhaloisopropoxy fiuoroalkyl telomer iodide having x CF; groups in the alkyl chain with an allyl alcohol having y-2 (i.e. 1-17) CH groups in the chain attached to the terminal OH group to produce an iodohydrin, followed by reducing the iodohydrin with zinc and alcohol, for example, to the corresponding alcohol.

When 2: is an odd number from 1 to 19 and y is an even or odd number from 4 to 19, the resulting alcohols can be prepared by reacting a perhaloisoalkoxy acid having an odd number of CF: groups in the fluoroalkane chain with Ag O to form the silver salt; reacting the silver salt with iodine to form the perhaloisoalkoxy perfluoroalkyl iodide, then reacting the perhaloisoalkoxy perfluoroalkyl iodide with an unsaturated alcohol such as allyl alcohol, and removing the iodine by reduction, such as with zinc and alcohol.

When x is an even number from 2 to 20 and y is 1 to 3, the alcohols can be made by converting the appropriate iodide to the pyrosulfate with S0,, or to the hydrosulfate with oleum, and hydrolysis of the fluoroalkoxy dialkyl pyrosulfate or hydrogen sulfate to the alcohol with aqueous acid.

Alcohols according to Formula IV having -CH chains of any desired length of two or more carbon atoms can be prepared by reacting a suitable telomer iodide with ethylene or with an ethylenically unsaturated alcohol such as allyl alcohol (CH =CHCH OH). In the latter case iodine is removed by reduction such as with zinc and alcohol.

When alcohols with an odd number of CF groups are desired, these can be obtained by reacting a perhaloisoalkoxy perfluoroalkyl iodide having an even number of -CF groups, with S0 esterifying the resulting reaction products, reducing the ester to the alcohol such as with LiAlH, and reacting the alcohol with p-toluene sulfonyl chloride and metallic iodide to form the iodide containing m-l (CF groups and one CH group.

The telomer starting materials for these reactions, and preparation thereof, are disclosed in our co-pending parent application Ser. No. 633,359, mentioned supra. Essentially, these telomer starting materials may be prepared by telomerizing corresponding telogens of the formula wherein R -R are as defined above and x is 1 or 2. The telomerization may be effected with tetrafluoroethylene followed by telomerization with ethylene, or with ethylene alone.

The reaction between the telogen and the tetrafluoroethylene and/or ethylene compound is carried out under free radical conditions. The free radicals are preferably produced by thermal initiation of the reaction and this is accomplished simply by heating the reactants to an elevated temperature. The reaction conditions normally will vary to some extent, depending on the particular reactants and the type of product desired. The temperature should normal-1y be between about 100 C. and 350 0., preferably between about ISO-200 C. Furthermore, although the reaction may be conducted at atmospheric pressure, superatmospheric pressures, for example, up to about 20,000 p.s.i.g. may be used with pressures between about 100 p.s.i.g. and about 10,000 p.s.i.g. being especially preferred. The reaction time is whatever is required to give satisfactory conversions and the optimum reaction time will depend on the particular reactants employed, on the temperature and on the method of unsaturated compound addition. For example, if the telogen and unsaturated compound are charged initially and heated to a temperature of about 200 C., the reaction is substantially complete in about 3 hours. On the other hand, if portionwise or continuous addition of tetrafiuoroethylene is used, for example, the reaction time is dependent on temperature and the rate of unsaturated compound addition. It is additionally believed that the chain length of the product obtained is influenced by the reaction time at least to a certain extent. Normally, the reaction time may range from about minutes to about 2 weeks, usually from about 1 hour to about 48 hours.

If desired, the reaction may be conducted by use of a catalyst or light of sufiicient intensity to initiate the free radical reaction. Illustrative free radical generating catalysts include azonitriles such as alpha,alpha'-azobisisobutyronitrile and organic peroxides such as benzoyl peroxide, acetyl peroxide and pelargonyl peroxide. The use of such initiators allows operation at a lower temperature but gives a somewhat more complex product mixture because of incorporation of catalyst fragments in the telomer mixture, or results in a higher molecular weight distribution in the product telomer.

The telomerization reaction may be carried out in various ways. For example, the telogen and the unsaturated compound may be introduced into an autoclave which is then sealed and heated, preferably with agitation such as by stirring or shaking, until the pressure drop indicates that the reaction has proceeded to the desired extent. In such an operation, the molar ratio of unsaturated compound to telogen is of importance in determining the molecular weight of the telomer product. In general, the average molecular weight of the product is dependent upon the molar ratio of unsaturated compound to telogen; the higher the unsaturated compound: telogen molar ratio, the higher will be the average molecular weight of the telomer product. The ratio of telogen to unsaturated compound may vary from about 1:75 to as high as 200:1, the preferred ratio for batchwise operation being about 1:1 to 2:1 in the production of relatively low molecular weight telomers, i.e. telomers containing up to about 6 or 7 monomer units per telomer molecule. On the other hand, in a constant pressure reaction, i.e. where a constant pressure of unsaturated compound is maintained above the liquid phase comprising the telogen during the reaction, the molecular weight of telomer product may be controlled by varying the pressure of the unsaturated compound. In general, the higher the pressure of the unsaturated compound, the higher the molecular weight of the telomer product.

The telomerization reaction inherently produces a mixture of telomers of varying chain lengths and corresponding varying molecular weights. The average chain length and the spread of molecular weight produced by the telomerization reaction may be controlled within limits as discussed above by varying the reactant proportions, reaction time, reaction temperature, reaction pressure and other reaction variables. If desired, individual telomer products can be separated from mixtures thereof by conventional separatory techniques, for example, by fractional distillation, fractional crystallization using an inert solvent such as diethyl ether, or the mixture of telomer products may be separated into fractions of narrower ranges of molecular weights having a desired viscosity or other properties.

The telogens of Formula VH for the preparation of the telomers described above may be prepared by reaction of an appropriate halogenated ketone with an ionizable fluoride salt to form a fluorinated organic salt and then reacting the organic salt with a halogen other than fluorine (e.g. iodine, bromine) and an appropriate olefin to form the desired polyhaloisoalkoxyalkyl halide. The reactions are more fully described in US. Pat. 3,453,333 to Litt et al., entitled Fluorinated Ethers, issued July 1, 11969, and copending application of Litt et al., Ser. No. 513,574, filed Dec. 13, 1965. For example, as is described in Examples 1 and 3 of US. Pat. 3,453,333, the telogen perfluoroisopropoxyethyl iodide, (CF CF0CF CF I, may be prepared by reacting hexafiuoroacetone with potassium fluoride in an acetonitrile solvent to produce the corresponding addition compound having the formula and thereafter reacting this addition compound with tetrafluoroethylene and iodine in the presence of an inert organic solvent to form the desired perfluoroisopropoxyethyl iodide, (CF )zCFO*CF CF I.

Illustrative compounds within the scope of the invention are shown as follows:

U (C F920 F O F20 FzCHzCHzD C-Xl-CzzH45 The following examples illustrate preparation of compounds of the invention. Parts and percentages are by weight unless otherwise indicated.

8 EXAMPLE 1 A 250 ml. 3-necked flask, equipped with a reflux condenser, thermometer, dropping funnel and agitator, was charged with 100 g. (0.305 mole) of The flask contents was stirred at 25 C. while 25 g. (0.317 mole) .of CHgCOCl were added dropwise through a dropping funnel. The addition was completed in about one hour. At the end of this period, the reaction mixture was further stirred at 50 C. for a period of five hours at the end of which period the evolution of HCl gas had ceased. The resulting product was then distilled under reduced pressure and 101 g. (0.27 mole) of a product identified as (B.P. 42 C./4 mm.) were obtained.

Analysis.-Calcd. for C9F11H703 (percent): C, 29.03; F, 56.18; H, 1.88. Found (percent): C, 28.52; F, 56.83; H, 1.94.

EXAMPLE 2 The procedure of Example 1 is repeated except that g. (0.142 mole) of (CF CFO (CF CF 3CH2CH2OH are reacted with 16 g. (0.15 mole) of CH (CH C0CL After distillation of the product mixture the following product is recovered:

We claim: 1. Compounds of the formula:

wherein (a) R -R are each independently selected from the group consisting of F, Cl and perfluoroalkyl groups having from 1 to 6 carbon atoms, and together can form a perfluorocycloalkylene group, with, the proviso that R -R may not contain more than two chlorine atoms, (b) x is an integer from 1-81, (c) y is an integer from 1-81, (d) R is a divalent alkylene group having from 1-22 carbon atoms, and (e) z is O or 1.

2. Compounds according to claim 1 in which at and y are each 120.

3. Compounds according to claim 1 in which x and y are each 1-15.

4. Compounds according to claim 3 in which Il -R are all F.

5. Compounds according to claim 4 in which z is 0.

6. Compounds according to claim 4 in which 2 is 1.

7. Compounds according to claim 6 in which R is a straight chain divalent alkylene group.

8. Compounds according to claim 7 in which 2: is an odd number from 1 to 19 and y is l.

9. Compounds according to claim 7 in which x is an even number from 2-20 and y is 1.

10. Compounds according to claim 7 in which x is an even number from 2-20 and y is an odd or even number from 3-20.

11. Compounds according to claim 1 in which x is an odd number from 1-19 and y is an even or odd number from 4-19.

12. Compounds according to claim 7 in which x is an 19. A compound according to claim 1 which is even number from 2-20 and y is 1-3.

13. Compounds according to claim 7 in which x and H y are even numbers from 2-14. (CF 9201 O(CF20FZ)3OH1CH2C1C18H"- 14. A compound according to claim 1 which is 20. A compound according to claim 1 which is H O onmcFoomomcmcmooom; (OFmcFowFgcmnomomo -n-o mi;

15.A mod d' t l' wh'h' co p un accor mg 0 c arm 1 10 1s References Cited 0 10 (CFQZCFO(CF2CFZ)QCHICHIOg(CHDZCHL 3 409 647 1 1 3 1258 i t i m f l 260-408 1 an e a 16. A compound according to claun 1 whlch is 3,523,133 8/1970 Mailey et aL 260L488 f 3,438,946 4/1969 Lichstein et a1. 260488 (oniono(cmcmnomoowmnom. 3,239,557 3/1966 Fasick 260-408 3,405,167 8/1968 Braun 260-488 17. A compound according to claim 1 Wind] is 3,047,610 7/1962 Brace et al- 260408 oFmoFoomo momomoiii-n-c snu. LEWIS GO'ITS, Primary Examiner 18. A compound according to claim 1 which is C. L. MILLS, Assistant Examiner Patent No.

Inventor(s) It is Column 2 QS Attest:

OHM PO-105O (10-69) and that said Letters Patent are hereby corrected as shown below:

McCOY M. GIBSON JR. Attesting Officer UNITED STATES PATENT oFFitE CERTiFICAiE 0F GORREQ'HQN Dated August 21 q 1973 Louis G. Anello, Morton H. Litt & Richard F. Sweeney certified that error appears in the above-identified patent line 60, delete "the preferred embodiment, z is L" and insert and most preferably are even integers from 2 1 4.

, column 8, line 73, delete "l" and insert 7 Signed and sealed this 1st day of October 197 i- C. MARSHALL DANN Commissioner of Patents USCOMM-DC 60375-P6Q Q U,S. GOVERNMENY PRINTING OFFICE: 1969 0-356-334 

